Adsorption and Recovery of Gold from Waste Thiourea Liquid by Biomass-Based Adsorbent
A method of selective adsorption and recovery of gold from waste thiourea liquid with biomass-based adsorbent prepared from phyllostachys pubescens was proposed.The charcoal,after being activated in H2O-CO2 atmosphere,has more nanopores with smaller size on its surface,compared to being activated by CO2 alone,which greatly increases the specific surface area of the adsorbent material.Based on exploration of the effects of factors,including type of adsorbent material,pH value,adsorbent dosage,adsorption temperature,and adsorption time,on the adsorption of gold in waste thiourea liquid,the appropriate adsorption conditions were obtained as follows:pH of 6,adsorbent dosage of 8 g/L,adsorption temperature of 25 ℃,and adsorption time of 3.5 h.It is found that activation in H2O-CO2 can bring the activated carbon with better adsorption effect,and the removal rate of gold from waste thiourea liquid by adsorption can exceed 96％.The adsorption isothermal model is used to fit the process of gold adsorption from waste thiourea liquid by the carbon activated in H2O-CO2 atmosphere,and the results show that such gold adsorption process follows Freundlich model and is a physical adsorption process.
adsorbentgoldcharcoalmodificationactivationactivated carbonwaste thiourea liquidadsorption model
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